ThePipingMart Blog Grades Magnesium AZ31B Alloy (UNS M11311) – Composition, Properties, and Uses

Magnesium AZ31B Alloy (UNS M11311) – Composition, Properties, and Uses

Magnesium AZ31B

This post will explore magnesium AZ31B composition, its physical and mechanical properties, heat treatment, machining, welding capabilities, and various applications across different industries.

What is Magnesium AZ31B?

Magnesium AZ31B is a popular magnesium alloy used in various industries due to its unique properties, lightweight and strength. It is a mixture of magnesium, aluminium, and zinc. This alloy has become preferred in automotive, aerospace, and biomedical industries because it is easy to machine and has high corrosion resistance.

Magnesium AZ31B Composition

Magnesium AZ31B is the most commonly used magnesium alloy that contains 3% aluminium and 1% zinc. It is an alloy with a good strength-to-weight ratio and excellent corrosion resistance.

Element Content (%)
Magnesium, Mg 97
Aluminum, Al 2.50 – 3.50
Zinc, Zn 0.60 – 1.40
Manganese, Mn  0.20
Silicon, Si 0.10
Copper, Cu 0.050
Calcium, Ca 0.040
Iron, Fe 0.0050
Nickel, Ni 0.0050

Magnesium AZ31B Mechanical Properties

Magnesium AZ31B has excellent mechanical properties, with a tensile strength of 230 MPa and a yield strength of 180 MPa. It is a flexible metal that can withstand high-stress levels, making it ideal for various industries like aerospace.

Properties Metric Imperial
Tensile strength 260 MPa 37700 psi
Yield strength (strain 0.200%) 200 MPa 29000 psi
Compressive yield strength (at 0.2% offset) 97 MPa 14100 psi
Ultimate bearing strength 385 MPa 55800 psi
Bearing yield strength 230 MPa 33400 psi
Shear strength 130 MPa 18900 psi
Shear modulus 17 GPa 2470 ksi
Elastic modulus 44.8 GPa 6498 ksi
Poisson’s ratio 0.35 0.35
Elongation at break (in 50 mm) 15% 15%
Hardness, Brinell (500 kg load, 10 mm ball) 49 49
Charpy impact (V-notch) 4.30 J 3.17 ft-lb

Magnesium AZ31B Physical Properties

Magnesium AZ31B has a density of 1.77 g/cm3, which makes it one of the lightest metals. It has a melting point of 650°C and a thermal conductivity of 76.9 W/mK. These properties make magnesium AZ31B easy to handle and manipulate.

Properties Metric Imperial
Density 1.77 g/cm3 0.0639 lb/in³

Magnesium AZ31B Uses

Magnesium AZ31B has many applications, including aerospace, automotive, medical equipment, sports equipment, and electronics. It is widely used in the aerospace industry for fabricating different aircraft components, such as brackets, engines, and aeroplane frames. Magnesium AZ31B is used in several other members of the automotive sector, including brake pedals, clutch pedals, and steering column components. This metal is also used in the medical industry for manufacturing medical implants, such as screws, pins, and plates.

Magnesium AZ31B Corrosion Resistance

Magnesium AZ31B has excellent corrosion resistance due to its zinc content. However, it is not entirely corrosion-resistant, particularly when exposed to aggressive environments. Therefore, it is essential to protect the magnesium alloy from corrosion and maintain it regularly.

Magnesium AZ31B Heat Treatment

Magnesium AZ31B can be heat-treated to improve its mechanical properties. Quenching magnesium AZ31B after heating it above 300°C makes it less brittle and more ductile. Annealing magnesium AZ31B before quenching increases its ductility and toughness.

Magnesium AZ31B Machining

Magnesium AZ31B is relatively easy to machine because of its low density and excellent machinability. However, due to its high reactivity to air and water, it is essential to use specialized equipment like dry machining and protective coatings during machining to prevent contamination.

Magnesium AZ31B Welding

Magnesium AZ31B can be welded with TIG (tungsten inert gas) welding or laser welding. It is essential to clean the surfaces of magnesium AZ31B properly before soldering to achieve better performance.


In conclusion, magnesium AZ31B is a unique alloy with high strength, low density, and excellent corrosion resistance. It has earned its reputation as one of the preferred materials in the aerospace, automotive, medical equipment, and electronics industries. As we have discussed, magnesium AZ31B’s properties make it easy to machine, weld, and heat treat. However, it is essential to protect the magnesium alloy from corrosion and maintain it regularly. Magnesium AZ31B is a versatile metal that can help engineers and manufacturers achieve their desired results while minimizing weight and maximizing performance.

Related Post